Proconsul

Arthur Hopwood coined the term Proconsul after the famous chimpanzee “Consul the Great.” Proconsul was a medium sized ape represented by four species: P. africanus; P. heseloni; P. major; and P. nyanzae. The best known of the “dental apes,” Proconsuls teeth displayed the Y-5 pattern characteristic of modern apes (Stanford). According to Hartwig, “Proconsul was an arboreal, quadrupedal catarrhine most similar in locomotive ability to a modern colobus monkey. This genus exhibited a short broad face with sweeping zygomatic arches, a broad nasal aperture, and a broad intraorbital region.” With an estimated cranial capacity of 167.3 c.c., Proconsuls brain size is larger than that of most modern monkeys (Murdock). Anthropologists have argued as to whether or not Proconsul retained a tail. According to Nakatsukasa, et al., “Recovered sacral vertebra indicates that Proconsul did not have a tail. The anatomical affinities of the last sacral and postsacral vertebra of monkeys and apes are clearly distinguishable. The resemblance of that vertebra in Proconsul to that of modern apes is remarkable.” The lack of a tail would suggest that they were lost early in hominoid evolution (Murdock). Proconsul is the earliest known hominoid discovered to date.

P. major

Proconsul major
• Le Gros Clark and Leakey, 1950
• BMNH M 16648, Right mandibular corpus with P4-M3
• 20 – 19 MYA
• Kenya & Uganda
P. major was the largest of the genus with postcrania remains indicating a body size of 166 pounds, comparable to a modern male orangutan (Hartwig). The species can be recognized dentally by its broad upper and lower incisors and lack of bilateral compression of the upper and lower canines. Postcranial remains consist of humeral, tibial, and femoral fragments along with a talus and partial calcaneous. Other than size, P. major has a very corresponding anatomy with the rest of the genus (Hartwig).

P. heseloni

Proconsul heseloni
• Walker, et al., 1993
• KNM-RU 2036, Partial skull and nearly complete female postcrania
• 18.5 – 17 MYA
• Kenya
P. heseloni has very well documented postcrania and weighed in slightly larger than a modern siamang with females approximately 22 pounds and males 44. The anatomy suggests a morphotype of primitive catarrhine and extant hominoid features. According to Hartwig, “The thorax, lumbar, and sacral regions, along with the illium are all long and narrow which is representative of monkeys. The limb bones were robust as was the hallux which provided for a powerful gripping ability.

P. nyanzae

Proconsul nyanzae
• Le Gros Clark and Leakey, 1950
• BMNH M 16647, Lower face and palate with: left C-M3 and right P3-M3
• 18.5 – 17 MYA
• Kenya
A large member of the genus. According to Hartwig, “the dentition is intermediate in size between P. heseloni and P. major and a suggested body size of approximately 88 lbs. for males and 62 lbs for females. The dentition shows less bilateral canine compression, broader lower molars, and greater size differential between M1 and M2 and between M1 and M2 than P. heseloni.”